Bw statistics

[Former Member]

HI all,

Could any one let me know what is BW statistics, where and how to maintain those statistics. Is there any difference between BW statistics and DB statistics. Defiantely i will assign points for great answers

Thanks

ratna

[Former Member · Accepted solution]

Hi Ratna!

I think here you can find all you need !

https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/com.sapportals.km.docs/documents/a1-8-4/how to set up bw statistics

Hope it helps!

Bye,

Roberto

[Former Member]

Raju -

Others have provided you with info on the BW Statistics - information about queries, loads, compresses, etc. It's all very good stuff. The BW OLAP Statisitcs are great way to see what is really going on in your BW. You can also get a lot of the query statistics from ST03N in Expert mode, e.g. how many times a query ran last week, avg run time, avg nbr of rows selected, etc.

The BW statistics info comes from a group of tables that start with RSDDSTAT. So if you are not loading the BW Statistics cubes, you can browse these tables. RSDDSTAT has the very granular info on each query that runs - how it performed, who ran it, when, etc. It would be a good expereience to browse RSDDSTAT to see what's there.

Database Statistics is something completely different. You can google 'cost based optimizer' if you want to learn more. Your database collects (or should) information about how many rows are in each table, the number of distinct values that occur in a column and a lot of stuff only a DBA could love. The database has a CBO (Cost Based Optimizer) that evaluates the queries you submit and uses the DB statistics to make decisions about which table to read first, the best way and order to join multiple tables, whether an index should be used to read the table, or if it would be better to perform a full scan (sequential read of the entire table).

You can refresh statistics for an InfoCube from the BW Admin workbench from one of the tabs under Manage.

Having accurate DB statistics is critical. The CBO may make a decision to read a table in an in efficient way if the DB statistics indicate there are only 10,000 rows in the table, when in fact there are 5 million. A bad decision on a large table can mean run time differences of orders of magnitude.

Decisions about when and how to collect statistics are very important to the successful operation of your BW.

This is a DBA's job. Hopefully your DBA is willing to invest time working with you to understand the BW and explain the methodlogy used on your BW. Unfortunately, in most shops, they concentrate only on the R3 side of things.

Pizzaman

[Former Member]

Hi,

BW statistics is tool for recording & reporting system activity & performance information.

for infocubes there is program called

SAP_ANALYZE_ALL_INFOCUBES

it gathers statistical information for all tables related to infocubes,including masterdata & aggregates.

it is multi cube named 0BWTC_C10, it contains six basic cubes, each of which stores specific performance information.

in tcode DB20 we can see the statistics of the cube by entering the f fact name.

for bw statictics refer the note 309955.

for DB statictics refer the note 588668.

Hope it helps

regards-

siddhu

Message was edited by: sidhartha

[Former Member]

Hi Ratna,

Refer this link:

http://help.sap.com/saphelp_nw04/helpdata/en/f2/e81c3b85e6e939e10000000a11402f/frameset.htm

Bye

Dinesh